Liquid crystal display elements have come to be used in watches, calculators, various measurement instruments, automobile panels, word processors, electronic organizers, printers, computers, televisions, clocks, advertising boards, and the like. Typical examples of the liquid crystal display mode include a TN (twisted nematic) mode, an STN (super twisted nematic) mode, and a vertical alignment mode and an IPS (in-plane switching) mode that use TFTs (thin film transistors). Liquid crystal compositions that are used in these liquid crystal display elements are required to be stable to external stimuli such as moisture, air, heat, and light, stay in a liquid crystal phase in a temperature range as wide as possible around room temperature, exhibit a low viscosity, and operate at a low driving voltage. Such a liquid crystal composition is constituted by several to several tens of compounds in order to optimize dielectric anisotropy (Δ∈), refractive index anisotropy (Δn), and the like for individual display elements.
Vertical alignment (VA) mode displays use liquid crystal compositions that have a negative Δ∈. Horizontal alignment displays employing the TN mode, the STN mode, the IPS (in-plane switching) mode, or the like use liquid crystal compositions that have a positive Δ∈. There is also a report on a driving mode in which a liquid crystal composition that has a positive Δ∈ is vertically aligned during no application of voltage and application of a horizontal electric field allows displaying. Thus, there is an increasing demand for a liquid crystal composition having a positive Δ∈. On the other hand, for all driving modes, there is a demand for low-voltage driving, high-speed response, and a wide operation temperature range. Specifically, there is a demand for Δ∈ that is positive and the absolute value of which is large, and for a low viscosity (η) and a high nematic phase-isotropic liquid phase transition temperature (Tni). On the basis of predetermined Δn×d, which is the product of Δn and cell gap (d), Δn of the liquid crystal composition needs to be appropriately adjusted so as to be in a range in accordance with the cell gap. In addition, in the case where liquid crystal display elements are applied to televisions and the like, high-speed response is a priority. Accordingly, liquid crystal compositions having a low rotational viscosity (γ1) are required.
A disclosed example of the configuration of a liquid crystal composition intended to provide high-speed response is a liquid crystal composition in which a compound that is represented by a formula (A-1) or (A-2) and is a liquid crystal compound having a positive Δ∈ and (B) that is a liquid crystal compound having a neutral Δ∈ are combined. Features of such liquid crystal compositions that the liquid crystal compound having a positive Δ∈ has a —CF2O— structure and the liquid crystal compound having a neutral Δ∈ has an alkenyl group, are well known in the field of liquid crystal compositions (Patent Literatures 1 to 4).

Meanwhile, as liquid crystal display elements are used in wider applications, the way of using the elements and the method of producing the elements have considerably changed. In order to adapt to such changes, optimization of characteristics other than known basic property values has come to be required. Specifically, for liquid crystal display elements using liquid crystal compositions, the VA mode, the IPS mode, and the like have come to be commonly used. Regarding the size of liquid crystal display elements, display elements having a very large size of 50 inches or more have come to be put into practical use and are being used. With the increase in substrate size, the main process of injecting a liquid crystal composition between substrates has changed from the conventional vacuum injection process to the one drop fill (ODF) process. Thus, a problem has arisen: dropping marks formed during dropping of liquid crystal compositions on substrates cause degradation of displaying quality.
In addition, in the step of producing a liquid crystal display element by an ODF process, an optimal amount of liquid crystal needs to be dropped in accordance with the size of the liquid crystal display element. A large deviation of the injection amount from the optimal value upsets the designed balance between the refractive index of and driving electric field of the liquid crystal display element, resulting in displaying failures such as occurrence of unevenness or poor contrast. In particular, for small liquid crystal display elements that are used in large quantities for recently popular smart phones, the optimal injection amount of liquid crystal is small so that it is difficult to adjust, to be within a certain range, the deviation of the amount from the optimal value. Accordingly, in order to maintain a high yield of liquid crystal display elements, for example, it is also necessary that the liquid crystal is less influenced by rapid pressure changes or impact within a dropping apparatus during dropping of the liquid crystal and the liquid crystal can be continuously dropped with stability for a long period of time.
As described above, for a liquid crystal composition used for an active-matrix-driving liquid crystal display element driven in TFT elements or the like, there has been a demand for a development in which, while features and performance such as high-speed response required for the liquid crystal display element are maintained and conventionally emphasized features of having a high resistivity and a high voltage holding ratio and being stable to external stimuli such as light and heat are ensured, the method for producing the liquid crystal display element needs to be considered.